1. Field of the Invention
The present invention is generally related to an exhaust system which is able to separate water from an exhaust stream and, more specifically, to an exhaust system that is able to separate water from an exhaust stream and which also effectively reduces the noise emanating from the exhaust system.
2. Description of the Prior Art
Many different types of exhaust mufflers are known to those skilled in the art. These mufflers are typically constructed to provide sound attenuation through the use of acoustic insulation and baffles. In certain applications, such as marine exhaust systems, water is injected into the exhaust stream to cool the temperature of the exhaust stream.
U.S. Pat. No. 5,625,173, which issued to Woods on Apr. 29, 1997, describes a single baffle linear muffler for marine engines. The improved muffler for silencing the exhaust emitted from a water cooled marine engine employs a first outer housing encompassing a generally cone shaped inner member and forming a silencing volume therebetween and an angularly disposed inter planar baffle, inlet path, outlet path, ramp, and aperture for exhaust gas and cooling water to fluidly communicate from an inlet to an outlet resulting in a diminution in flow velocity so as to attenuate the exhaust noise.
U.S. Pat. No. 5,615,893, which issued to Woods on Apr. 1, 1997, describes a reverse entry muffler with surge suppression feature. The improved muffler for silencing the exhaust emitted from a marine engine employs a reverse entry inlet conduit, an attenuation chamber and an outlet conduit whereby exhaust gas and liquid are communicated through an inlet conduit and into the attenuation chamber against the direction of the outlet stream. Upon entering the attenuation chamber exhaust gases and liquids reflect the inner walls of the chamber and incoming exhaust thereby attenuating exhaust noise until they are finally forced out of the attenuation chamber through the outlet conduit. The reverse entry design of the muffler provides protection against backwardly flowing water that commonly enters a marine exhaust system by orienting the direction of inlet flow at an angle which is greater than 0 degrees but less than 90 degrees relative to the direction of output flow from the muffler.
U.S. Pat. No. 5,504,280, which issued to Woods on Apr. 2, 1996, discloses a muffler for marine engines. The muffler is intended to silence the exhaust emitted from a water cooled marine engine comprising a housing enclosure having a corrugated spacing means disposed within the housing partitioned by an angularly disposed inner planar baffle, the housing having an inlet for the exhaust gas and cooling water to fluidly communicate with a lower silencing chamber wherein the exhaust gas and cooling water are forced through a spacer passageway formed from the corrugated spacing means into an upper silencing chamber resulting in flow reversal and diminution in flow velocity so as to attenuate the exhaust noise, the exhaust gas and cooling water exiting the upper silencing chamber through an outlet fluidly communicated therewith and disposed collinearly with the input. The upper silencing chamber acts as a back flow preventor.
U.S. Pat. No. 5,444,196, which issued to Woods on Aug. 22, 1995, describes an in line insertion muffler for marine engines. The muffler employs a first housing encompassing a second housing which is partitioned by an angularly disposed inner planar baffle further having an inlet for exhaust gas and cooling water to fluidly communicate into an inlet chamber of the second housing resulting in a diminution in flow velocity so as to attenuate the exhaust noise, the exhaust gas and cooling water exiting the inlet chamber through an aperture fluidly communicated therewith into a silencing volume formed by an area between the first and second housing and forced through an aperture into an outlet chamber of the second housing. The outlet chambers acts as a back flow preventor.
U.S. Pat. No. 5,196,655, which issued to Woods on Mar. 23, 1993, describes a muffler for a marine engine. It comprises a housing enclosure partitioned by an angularly disposed inner planar baffle, the housing having an inlet for the exhaust gas and cooling water to fluidly communicate with a lower silencing chamber wherein the exhaust gas and cooling water are forced through a central passageway into an upper silencing chamber resulting in flow reversal and diminution in flow velocity so as to attenuate the exhaust noise, the exhaust gas and cooling water exiting the upper silencing chamber through an outlet fluidly communicated therewith and disposed collinearly with the input. The upper silencing chamber acts as a back flow preventor.
U.S. Pat. No. 5,094,640, which issued to Burdick et al. on Mar. 10, 1992, describes a marine engine noise suppressor with swim platform. The sound muffling devices for marine engines are installed on the external portion of the transom of a marine vessel and attached in such a way that any breakdown within the silencer causes no discharge of exhaust gases or cooling fluids into the interior of the vessel and the gases and cooling fluid continue to be discharged overboard. The silencers are designed to reduce, substantially, the noise level emitted by the engine under operation by the efficient mixture of gases and water through a series of baffles, with low resistance to gas flow that does not diminish engine efficiency.
U.S. Pat. No. 4,977,977, which issued to Von Widmann et al. on Dec. 18, 1990, describes a marine engine external exhaust noise suppressor with swim platform. The sound muffling devices for marine engines are installed on the external portion of the transom of a marine vessel and are attached in such a manner that any breakdown within the silencer causes no discharge of exhaust gases or cooling fluids into the interior of the vessel and the gases and cooling fluids continue to be discharged overboard. The device receives exhaust gas and cooling water from an exhaust pipe passing through the transom at the side of the boat and directs the gas to the center where it is exhausted. The device is designed to be used in pairs, with one of each pair of engines mounted side by side with an integral swim platform for its upper surface.
U.S. Pat. No. 4,781,021, which issued to Winberg on Nov. 1, 1988, describes a marine engine exhaust muffler assembly that includes inlet and outlet members, the axes of which are offset from each other. A muffler housing is disposed between the inlet and outlet members and forms a chamber having disposed therein an angular multi-layered cartridge, and with the layers having a multiplicity of perforations therein for passage of exhaust gases and spent engine cooling water therethrough. The water assists in keeping the muffler clean. An imperforate arcuate blocking plate is nested within the lower portion of the cartridge to permit accumulation of the spent engine cooling water within the cartridge to aid in noise reduction at certain engine speeds. The blocking plate is provided with a relief opening means for assisting in water drainage upon engine shutoff.
U.S. Pat. No. 4,184,566, which issued to Baker et al. on Jan. 22, 1980, describes a marine engine noise suppressor. The noise suppressor for an internal combustion engine exhaust, adapted for marine use wherein water coolant is discharged into the chamber of a single walled riser and partially vaporized by the exhaust gases directed into the dome thereof for downward redirection and discharge from the lower portion of the riser chamber through a muffler element, and preferably through the hull chest and/or cover of a jet pump drive acting as the final noise barrier to atmosphere.
U.S. Pat. No. 4,100,994, which issued to Stuart on Jul. 18, 1978, describes a marine exhaust silencer. The silencer quiets the exhaust output from a marine engine by injecting a spray of cooling water into the exhaust passageway to mix with and cool the exhaust gases before output from the passageway. The exhaust passageway preferably enlarges substantially in cross-sectional area in the region where the mixing occurs between the injected water and the exhaust gases for enhancing the cooling effect. An inlet scoop receives water as the boat moves forward, and the water is forced through a line and into the exhaust passageway in a way that breaks the water into droplets for contacting and cooling the exhaust gases. A mute that is preferably conical in shape and centered in the exhaust outlet also cooperates to reduce the exhaust noise.
U.S. Pat. No. 4,019,456, which issued to Harbert on Apr. 26, 1977, describes a marine wet exhaust system and improvements in powered marine vessels. The exhaust gas cooling water separation chamber is combined with a gas collection chamber and gas acceleration and gas flow-shaping conduit means. The entrance of the separation chamber is connectable to water coolant and gas exhaust tubes from a marine engine. The separation chamber is fitted with a water deflector disposed below the gas exit from that chamber while a gas dam is disposed in the water exit from that chamber, the entrance and water exit going below the deflector level.
The United States patents described above are explicitly incorporated herein by reference in the following description.